Conventionally, to evaluate the cardiac function objectively and quantitatively, techniques have been available that obtain a motion index regarding, for example, a displacement or a strain of tissue in the heart. For example, an ultrasonic diagnostic apparatus collects three-dimensional ultrasonic image data of the heart in a time series, performs pattern matching of a local region on ultrasonic images, performs tracking of the local region, and thereby estimates the motion index of the heart. The ultrasonic diagnostic apparatus then generates an image of the heart (or a cardiac ventricle, a cardiac atrium, or another part) included in a region of interest defined by an operator by rendering processing, and displays the estimated motion index on a rendering image with color coding applied thereto, for example.